Wear resistant rubber hose

ABSTRACT

A wear resistant rubber hose for transferring fluid containing abrasive material such as crushed stone, coral, etc. comprises an inner surface rubber and a filling body having a rigidity which is considerably higher than that of the inner surface rubber embedded directly inside the inner peripheral surface thereof. Two embodiments of the filling body are provided. In one embodiment, the filling body is composed of a chain-shaped continuous body, while in another embodiment the filling body is composed of a reinforcing ring comprising a circumferentially wound core and sphere-shaped rotary bodies fitted onto the core.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention relates to wear resistant rubber hoses and moreparticularly to a wear resistant rubber hose for transferring fluidcontaining abrasive material such as crushed stone, coral, etc.

(2) Description of the Prior Art

In transferring mud dug from the sea-bed together with the sea water bymeans of a conventional rubber hose, sharp corners of the crushed stoneor coral mixed in the mud strike against the inner surface of the rubberhose, thus inducing the premature tear failure thereof and hencedeteriorating its durability.

SUMMARY OF THE INVENTION

An object of the invention, therefore, is to provide a wear resistantrubber hose which can eliminate the above described drawback which hasbeen encountered with the prior art technique, that is, which has asignificantly high durability for a total period in the use of rubberhose.

A feature of the invention is the provision in a wear resistant rubberhose comprising an inner surface rubber, a reinforcing layer forcovering said inner surface rubber and an outer cover rubber forcovering said reinforcing layer, of the improvement comprising a fillingbody having a rigidity which is considerably higher than that of saidinner surface rubber and embedded directly inside the inner peripheralsurface thereof.

The filling body may be composed of hard particles, preferably a steelchain. The hard particles can improve the wear resistant property of theinner periphery of the inner surface rubber. But, if the inner surfaceof the rubber becomes damaged to expose the hard particles, they tend tobe easily dug out. As a result, the inner surface rubber becomessignificantly worn, particularly after a given period in the use of therubber hose.

In accordance with the invention, in order to eliminate such drawback,the filling body is composed of a chain-shaped continuous body woundaround a center axis of the hose along the inner periphery thereof.Alternatively, the filling body may be composed of a chain consisting ofa series of links connected one to another and each formed of an openring whose opposed ends form a gap therebetween. The chain may alsoconsist of a series of links connected one to another and each formed ofa closed ring and connected to adjacent links with a gap formedtherebetween. In the final embodiment, the filling body may be composedof a reinforcing ring comprising a number of spaced apartcircumferentially wound cores surrounding the center axis of the hoseand arranged side by side in the axial direction of the hose and anumber of spaced apart sphere-shaped rotary bodies fitted onto eachcircumferentially wound core.

DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail with reference tothe accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a conventional rubber hoseillustrating the mode of gradually damaging its inner surface rubber byan abrasive fluid;

FIG. 2 is a cross-sectional view of one embodiment of a wear resistantrubber hose according to the invention;

FIG. 3a is a partial perspective view of a preferred embodiment of afilling body used in the rubber hose shown in FIG. 2;

FIG. 3b is a partial perspective view of another preferred embodiment ofa filling body used in the rubber hose shown in FIG. 2;

FIG. 4 is a perspective view of another embodiment of a wear resistantrubber hose according to the invention, a part being broken away so asto show a further preferred embodiment of a filling body used therein;

FIG. 5 is a partial cross-sectional view of the rubber hose shown inFIG. 4 showing its initial condition at a given period of time in theuse of the rubber hose; and

FIG. 6 is a partial cross-sectional view of the rubber hose shown inFIG. 4 and showing its condition on and after a given period of time inthe use of the rubber hose.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1 is shown a conventional rubber hose 1. Such rubber hose 1usually has an inner diameter of the order of 760 mm and a length of theorder of 1.7 m and comprises an inner surface rubber 2 having athickness of about 80 mm, a reinforcing layer 3 covering the outerperiphery of the inner surface rubber 2 and an outer cover rubber 4covering the reinforcing layer 3 and provided at its both ends with ametal flange 5 made integral therewith. If such conventional rubber hoseis used for transferring mud together with sea water, abrasive material6 contained in the fluid is struck against the inner surface rubber 2,thereby damaging it as shown by the undulations in FIG. 1.

In FIG. 2 is shown one embodiment of a wear resistant rubber hoseaccording to the invention. In the present embodiment, a rubber hose 1is provided directly inside of the inner surface rubber 2 with a numberof spaced apart chain-shaped continuous bodies 7. These chain-shapedcontinuous bodies 7 are arranged side by side along the inner peripheryof the inner surface rubber 2 and wound around the center axis of therubber hose 1 and embedded therein. It is preferable to make use of achain 7 consisting of a series of links connected one to another andwound helically around the center axis of the rubber hose 1. The innersurface rubber 2 is covered with a reinforcing layer 3 which canwithstand the internal pressure applied to the rubber hose 1 and thereinforcing layer 3 is covered with an outer cover rubber 4 having athickness of the order of 5 mm.

In FIG. 3a is shown one preferred embodiment of a filling body accordingto the invention. In the present embodiment, the filling body iscomposed of a steel chain 7 consisting of a series of links connected toone another. Each link is formed of an open C-shaped ring whose opposedends form a gap 8 therebetween. Each link has a diameter of the order of10 mm.

In FIG. 3b is shown another preferred embodiment of a filling bodyaccording to the invention. In the present embodiment, the filling bodyis composed of a chain 7 consisting of a series of links connected toone another. Each link is formed of a closed ring and connected toadjacent links with a gap 9 formed therebetween.

In the rubber hose constructed as above described according to theinvention, in its initial condition shown in FIG. 2, the thickness ofthe inner surface rubber 2 is large and the steel chain 7 constitutingthe filling body functions to reinforce the inner surface rubber 2 andhence improve the initial durability thereof against the abrasive fluid.

If the inner surface rubber 2 becomes worn to reduce its thickness, thesteel chain 7 is exposed out of the inner periphery of the inner surfacerubber 2 and brought into contact with the fluid being transferred orthe abrasive material such as crushed stones, coral, etc. containedtherein. As a result, it is possible to effectively prevent any furtherwear of the inner surface rubber 2 and hence improve the durability ofthe rubber hose after a given period in the use thereof.

In the case of using as the filling body the steel chain 7 shown in FIG.3a, the steel chain 7 functions to particularly increase the resistanceagainst the digging action due to the abrasive fluid and hence furtherimprove the durability of the rubber hose. That is, if the internalpressure of the fluid being transferred is exerted on the inner surfacerubber 2, a local stress is produced in that part of the inner surfacerubber 2 which is bound by the steel chain 7. As a result, the chain 7formed of the C-shaped open rings becomes resiliently deformed toeffectively alleviate the local stress concentrated into the innersurface rubber 2.

The steel chain 7 shown in FIG. 3b also functions to particularlyincrease the resistance against the digging action due to the abrasivefluid and hence further improve the durability of the rubber hose.

That is, if the internal pressure of the fluid being transferred isexerted on the inner surface rubber 2, a local stress is produced inthat part of the inner surface rubber 2 which is bound by the steelchain 7. As a result, the chain 7 formed of closed links connected witheach other through the gaps 9 functions to compress and deform therubber in the gaps 9 and hence absorb and effectively alleviate thelocal stress concentrated into the inner surface rubber 2.

As stated hereinbefore, the rubber hose for transferring fluidcontaining abrasive material according to the invention cansignificantly improve the wear resistant property of the inner surfacerubber thereof and hence effectively improve the durability of therubber hose.

In FIG. 4 is shown another embodiment of a wear resistant rubber hoseaccording to the invention. In the present invention, use is made of areinforcing ring R as the filling body. The reinforcing ring R iscomposed of a number of sphere-shaped rotary bodies 10 each having adiameter of the order of 30 mm and circumferentially wound cores 11spaced apart from each other and each formed of a steel cord usuallyused as a tire cord and for rotatably supporting respective rotarybodies 10. In the present embodiment, the reinforcing ring R ishelically wound around the center axis of the hose 1 along its innerperiphery and embedded in an inner surface rubber 2 having a thicknessof the order of 80 mm.

Similar to the embodiment shown in FIG. 2, the inner surface rubber 2 iscovered with a reinforcing layer 3 which can withstand the internalpressure applied by the abrasive fluid to the hose 1 and which is alsocovered with an outer cover rubber 4 having a thickness of the order of5 mm.

In the rubber hose constructed as above described according to theinvention, in the beginning the thickness of the inner surface rubber 2is large as shown in FIG. 5, and the reinforcing ring R embedded in itsurface rubber 2 functions to reinforce the inner against the abrasivefluid and hence improve the initial durability of the rubber hose. Ifthe inner surface rubber 2 becomes worn and thin as shown in FIG. 6, therotary bodies 10 are exposed out of the inner periphery of the innersurface rubber 2 and brought into contact with the fluid beingtransferred or abrasive material such as crushed stone or coralcontained therein and hence become rotated. As a result, the frictionalresistance of the rotary body 10 against the abrasive fluid is decreasedto effectively prevent any further progress of wear of the inner surfacerubber 2, thereby improving the durability of the rubber hose 1.

In order to prevent the rotary bodies 10 from being displaced in theaxial direction of the rubber hose 1, it is preferable that thecircumferentially wound core 11 is provided with projections 11a. Inaddition, it is desirous to cover the rotary bodies 10 with cellophanepaper or a mold releasing agent layer in the case of embedding it in theinner surface rubber 2.

In the present embodiment, the circumferentially wound core 11 ishelically arranged, but it may alternatively be composed of a pluralityof annular rings spaced apart from each other and coaxially arrangedside by side in the axial direction of the hose 1.

As stated hereinbefore, the rubber hose for transferring a fluidcontaining abrasive material according to the present embodiment canalso effectively improve the durability of the rubber hose.

What is claimed is:
 1. In a wear resistant rubber hose comprising aninner layer of surface rubber, an intermediate reinforcing layersurrounding said inner layer of surface rubber and an outer cover rubberlayer surrounding said reinforcing layer, the improvements comprising: acord having a plurality of spaced spherical bodies threaded thereon inthe manner of a string of beads, said cord being helically wound aroundthe central longitudinal axis of the hose, having a rigidityconsiderably higher than that of said inner layer of surface rubber, andbeing completely embedded inside the inner layer of surface rubber. 2.The rubber hose according to claim 1, further comprising a plurality ofprojections on said cord individually disposed between adjacentspherical bodies to prevent them from sliding along the cord.